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  Ishikawa, T.; Watanabe, T.; Hara, S.; Islam, A.T.M.N.; Wheeler, E.M.; Lake, B.: Ultrasound velocity measurements in orbital-degenerate frustrated spinel MgV₂O₄. Journal of Physics: Conference Series 592 (2015), p. 012107/1-4

10.1088/1742-6596/592/1/012107
Open Access Version

Abstract:
Ultrasound velocity measurements of the orbital-degenerate frustrated spinel MgV2O4 are performed in the disorder-free high-purity single crystal which exhibits successive structural and antiferromagnetic phase transitions, and in the disorder-introduced single crystal which exhibits spin-glass-like behavior. The measurements reveal coexisting two types of anomalous temperature dependence of the elastic moduli in the cubic paramagnetic phase: Curie-type softening with decreasing temperature, and softening with a characteristic minimum with decreasing temperature. These elastic anomalies should respectively originate from the coexisting orbital fluctuations and spin-cluster excitations.